Bump semver and pg-promise

Bumps [semver](https://github.com/npm/node-semver) to 6.3.1 and updates ancestor dependency [pg-promise](https://github.com/vitaly-t/pg-promise). These dependencies need to be updated together.


Updates `semver` from 4.3.2 to 6.3.1
- [Release notes](https://github.com/npm/node-semver/releases)
- [Changelog](https://github.com/npm/node-semver/blob/v6.3.1/CHANGELOG.md)
- [Commits](npm/node-semver@v4.3.2...v6.3.1)

Updates `pg-promise` from 10.5.3 to 10.15.4
- [Release notes](https://github.com/vitaly-t/pg-promise/releases)
- [Commits](vitaly-t/pg-promise@10.5.3...10.15.4)

---
updated-dependencies:
- dependency-name: semver
  dependency-type: indirect
- dependency-name: pg-promise
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -59,7 +59,7 @@
     "mysql2-stream-fix": "3.9.1",
     "node-firebird": "1.1.8",
     "pg": "8.0.3",
-    "pg-promise": "10.5.3",
+    "pg-promise": "10.15.4",
     "pg-query-stream": "3.0.7",
     "sax-stream": "1.3.0",
     "shortid": "2.2.15",